In analog photography, tray development is the manual development of films and photo papers in open trays. These are filled with developing baths, usually a developing liquid, a stop bath and a fixer . The material to be developed is dipped into the baths one after the other with tongs and remains in them for the necessary time. The shells are moved during development.
This development method is mainly used in the preparation of black and white papers. The room can be illuminated with a darkroom lamp without causing the photo paper to blacken. A darkroom lamp can also be used with colored paper, but the light intensities that can be used are significantly lower. Footage typically requires red light, while bromide silver photo paper displays yellow or green light.
When developing the shell, special effects can be achieved through post-exposure etc.